Nearly 800,000 people suffer a stroke each year in the US and the cost of stroke reaches $105 billion annually. Stroke is also a leading cause of disability in the US. Post-stroke disability is dramatically reduced among patients who receive tissue plasminogen activator (tPA). For clinical effectiveness, tPA must be administered within 4.5 hours from the start of stroke symptoms. Unfortunately, tPA is vastly underutilized with about 3% of stroke patients receiving tPA. The majority of patients fail to receive tPA because they arrive to the hospital after the treatment time window has elapsed (this barrier to tPA administration is known as prehospital delay). Researchers have shown that if 911 were called at the time of stroke onset, over 28% of all stroke patients would receive tPA. Therefore, translational research to increase stroke preparedness (defined as the ability to recognize stroke warning signs and call 911 immediately) is urgently needed. However, the field of stroke preparedness is severely limited by the absence of intermediate end points to test behavioral interventions. Before embarking on large scale, expensive, community intervention trials, phase 2 studies using intermediate end points are needed. An intermediate end point allows for testing of several interventions (phase 2 studies) before deciding on the most promising intervention that warrants phase 3 testing. Intermediate end points also facilitate testing interventions for selected populations such as high risk groups like racial/ethnic minorities or those with low socioeconomic status, rather than an entire community. In this project, we will develop and validate a psychometrically rigorous test of stroke preparedness using video vignettes - the video stroke action test (video-STAT). Because of the increased burden of stroke among African Americans, Hispanics and those with low socioeconomic status, we will oversample from these groups in development and validating of the video-STAT. At completion of this study, an innovative stroke preparedness intermediate end point will be created and critical steps toward validating it will be performed. As the US population ages, stroke will only claim more victims and at greater expense to individuals, families and society. It is critical that we rapidly develop rigorous scientific interventions that increase delivery of acute stroke therapy to decrease post-stroke disability and reduce the enormous impact of this devastating disease.